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From: Jamie Lokier <jamie@shareable.org>
To: "Ihar 'Philips' Filipau" <filia@softhome.net>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: nasm over gas?
Date: Mon, 8 Sep 2003 17:17:29 +0100	[thread overview]
Message-ID: <20030908161729.GB26829@mail.jlokier.co.uk> (raw)
In-Reply-To: <3F5C7009.4030004@softhome.net>

Ihar 'Philips' Filipau wrote:
>   It will depend on arch CPU only in case if you have unlimited i$ size.
>   Servers with 8MB of cache - yes it is faster.
>   Celeron with 128k of cache - +4bytes == higher probability of i$ miss 
> == lower performance.

Higher probability != optimal performance.

It depends on your execution context.  If it's part of a tight loop
which is executed often, then saving a cycle in the loop gains more
performance than saving icache, even on a 128k Celeron.

The execution context can depend on the input to the program, in which
case the faster of the two code sequences can depend on the program's
input too.  Then, for optimal performance, you need to profile the
"expected" inputs.

> P.S. Add having good macroprocessor for assembler is a must: CPP is 
> terribly stupid by design. I beleive gas has no preprocessor comparable 
> to masm's one? I bet they are using C's cpp.

You obviously have not read the GAS documentation.

It has quite a good macro facility built in.

-- Jamie

  parent reply	other threads:[~2003-09-08 16:17 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <rZQN.83u.21@gated-at.bofh.it>
     [not found] ` <saVL.7lR.1@gated-at.bofh.it>
     [not found]   ` <soFo.16a.1@gated-at.bofh.it>
     [not found]     ` <ssJa.6M6.25@gated-at.bofh.it>
     [not found]       ` <tcVB.rs.3@gated-at.bofh.it>
2003-09-08 12:03         ` nasm over gas? Ihar 'Philips' Filipau
2003-09-08 13:53           ` Richard B. Johnson
2003-09-08 16:10             ` Jamie Lokier
2003-09-08 16:17           ` Jamie Lokier [this message]
2003-09-08 16:45             ` Ihar 'Philips' Filipau
2003-09-08 16:58               ` Jamie Lokier
2003-09-08 17:59           ` William Lee Irwin III
     [not found] ` <uw6d.3hD.35@gated-at.bofh.it>
     [not found]   ` <uxED.5Rz.9@gated-at.bofh.it>
     [not found]     ` <uYbM.26o.3@gated-at.bofh.it>
     [not found]       ` <uZUr.4QR.25@gated-at.bofh.it>
     [not found]         ` <v4qU.3h1.27@gated-at.bofh.it>
     [not found]           ` <vog2.7k4.23@gated-at.bofh.it>
2003-09-13 23:57             ` stack alignment in the kernel was " Andi Kleen
2003-09-14 13:54               ` Jamie Lokier
2003-09-14 14:13                 ` Andi Kleen
2003-09-14 15:56                   ` Jamie Lokier
2003-09-14 22:27                 ` Jan Hubicka
     [not found] <tt0q.6Rc.17@gated-at.bofh.it>
     [not found] ` <tt0r.6Rc.19@gated-at.bofh.it>
     [not found]   ` <tt0r.6Rc.21@gated-at.bofh.it>
     [not found]     ` <tt0r.6Rc.23@gated-at.bofh.it>
     [not found]       ` <tt0r.6Rc.25@gated-at.bofh.it>
     [not found]         ` <tt0q.6Rc.15@gated-at.bofh.it>
     [not found]           ` <tyCN.6RD.13@gated-at.bofh.it>
2003-09-08 20:08             ` Ihar 'Philips' Filipau
     [not found] <snJB.8dk.25@gated-at.bofh.it>
     [not found] ` <snTm.8qD.41@gated-at.bofh.it>
     [not found]   ` <sTpW.18Z.19@gated-at.bofh.it>
     [not found]     ` <teE5.2XZ.9@gated-at.bofh.it>
2003-09-08 12:07       ` Ihar 'Philips' Filipau
2003-09-05 13:57 John Bradford
2003-09-05 15:39 ` Mehmet Ceyran
2003-09-06 20:24   ` David B. Stevens
  -- strict thread matches above, loose matches on Subject: below --
2003-09-05 12:25 John Bradford
2003-09-05 12:25 ` Fruhwirth Clemens
2003-09-06 22:08   ` Herbert Poetzl
2003-09-07 20:40     ` Fruhwirth Clemens
2003-09-05 13:20 ` Richard B. Johnson
2003-09-05 12:21 John Bradford
2003-09-04 10:42 Fruhwirth Clemens
2003-09-04 12:32 ` Antonio Vargas
2003-09-04 13:44 ` Yann Droneaud
2003-09-04 14:05   ` Richard B. Johnson
2003-09-04 14:21     ` Sean Neakums
2003-09-04 14:33       ` Richard B. Johnson
2003-09-04 15:09         ` Yann Droneaud
2003-09-04 14:55     ` Yann Droneaud
2003-09-05 21:16       ` George Anzinger
2003-09-04 14:57   ` Michael Frank
2003-09-04 15:43     ` Fruhwirth Clemens
2003-09-04 22:28     ` insecure
2003-09-05 12:59       ` Michael Frank
2003-09-05 17:28         ` insecure
2003-09-05 17:45           ` Jörn Engel
2003-09-06 17:18             ` insecure
2003-09-07 18:49           ` Eric W. Biederman
2003-09-07 19:30             ` Jamie Lokier
2003-09-09 21:37               ` insecure
2003-09-09 21:34             ` insecure
2003-09-11 11:07               ` Ricardo Bugalho
2003-09-12 15:26                 ` insecure
2003-09-12 17:27                   ` Ricardo Bugalho
2003-09-12 22:17                     ` Jörn Engel
2003-09-13 19:25                       ` Jamie Lokier
2003-09-13 19:51                         ` Jörn Engel
2003-09-11 14:03               ` Eric W. Biederman
2003-09-11 17:05                 ` Jamie Lokier
2003-09-09 20:56           ` Pavel Machek
2003-09-05 13:27       ` Jesse Pollard
2003-09-05 23:51     ` Aaron Lehmann
2003-09-06  1:41       ` Valdis.Kletnieks
2003-09-04 14:56 ` Yann Droneaud
2003-09-05 11:42 ` Jörn Engel
2003-09-05 12:04   ` Fruhwirth Clemens
2003-09-05 12:37     ` Jörn Engel

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